import java.sql.*;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
      //  m1();
        //m2();
        //m3();
       //m4();
        m5();
    }
    private static void m1(){
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;

//1.加载驱动

        try {
            Class.forName("com.mysql.cj.jdbc.Driver");


            //2.创建连接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection = DriverManager.getConnection(url, "root", "huang123");
            /*if(connection != null){
                System.out.println("连接成功");
            }*/
            //3.写sql
            String sql = "select * from user";

            //4.预编译sql
            preparedStatement = connection.prepareStatement(sql);

            //5.执行sql
            resultSet = preparedStatement.executeQuery();


            //6.遍历结果
            while (resultSet.next()) {
                int id = resultSet.getInt(1);
                String name = resultSet.getString(2);
                String pass = resultSet.getString(3);
                System.out.println(id + "----" + name + "----" + pass);
            }


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
//7.关闭资源

            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
    private static void m2(){
        //键盘录入
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入用户名：");
        String name = scanner.nextLine();
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        ResultSet resultSet = null;

//1.加载驱动

        try {
            Class.forName("com.mysql.cj.jdbc.Driver");


            //2.创建连接
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            connection = DriverManager.getConnection(url, "root", "huang123");
            //if(connection != null){
              //  System.out.println("连接成功");
            //}
            //3.写sql
            String sql = "select * from user where name like ?";
            preparedStatement = connection.prepareStatement(sql);
            preparedStatement.setString(1,"%"+name+"%");
            resultSet = preparedStatement.executeQuery();

            //4.预编译sql



            //6.遍历结果
            while (resultSet.next()) {
                int id = resultSet.getInt("id");
                String username = resultSet.getString("name");
                String pass = resultSet.getString("pass");
                System.out.println("ID:"+ id +", Name:+" + pass);
            }


        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } catch (SQLException e) {
            throw new RuntimeException(e);
        } finally {
//7.关闭资源

            try {
                if (resultSet != null) {
                    resultSet.close();
                }
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
    private static void m3() {
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            try {
                connection = DriverManager.getConnection(url, "root", "huang123");
                // if(connection != null){
                System.out.println("连接成功");
                // }
                //3.sql
                String sql = "insert into user(name,pass)values(?,?)";
                //4.预编译sql
                preparedStatement = connection.prepareStatement(sql);
                preparedStatement.setString(1, "张三");
                preparedStatement.setString(2, "123456");
                int result = preparedStatement.executeUpdate();
                if (result > 0) {
                    System.out.println("添加成功");
                } else {
                    System.out.println("添加失败");
                }
            }

            catch (SQLException e) {
                throw new RuntimeException(e);
            }
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } finally {

            try {
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
}
    private static void m4(){
        Connection connection = null;
        PreparedStatement preparedStatement = null;
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
            String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
            try {
                connection = DriverManager.getConnection(url, "root", "huang123");
                // if(connection != null){
                // System.out.println("连接成功");
                // }
                //3.sql
                String sql = "update user set name=?,pass=?where id=?";
                //4.预编译sql
                preparedStatement = connection.prepareStatement(sql);
                preparedStatement.setString(1, "张三");
                preparedStatement.setString(2, "888");
                preparedStatement.setInt(3, 7);
                int result = preparedStatement.executeUpdate();
                if (result > 0) {
                    System.out.println("修改成功");
                } else {
                    System.out.println("修改失败");
                }


            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        } catch (ClassNotFoundException e) {
            throw new RuntimeException(e);
        } finally {

            try {
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (preparedStatement != null) {
                    preparedStatement.close();
                }
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }
        }
    }
        private static void m5() {
            Connection connection = null;
            PreparedStatement preparedStatement = null;
            try {
                Class.forName("com.mysql.cj.jdbc.Driver");
                String url = "jdbc:mysql://127.0.0.1:3306/jdbc?characterEncoding=utf-8";
                try {
                    connection = DriverManager.getConnection(url, "root", "huang123");
                    // if(connection != null){
                    // System.out.println("连接成功");
                    // }
                    //3.sql
                    String sql = "delete from user where id=?";
                    //4.预编译sql
                    preparedStatement = connection.prepareStatement(sql);
                    preparedStatement.setObject(1,7);
                    int result = preparedStatement.executeUpdate();
                    if (result > 0) {
                        System.out.println("删除成功");
                    } else {
                        System.out.println("删除失败");
                    }


                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            } catch (ClassNotFoundException e) {
                throw new RuntimeException(e);
            } finally {

                try {
                    if (preparedStatement != null) {
                        preparedStatement.close();
                    }
                    if (preparedStatement != null) {
                        preparedStatement.close();
                    }
                    if (connection != null) {
                        connection.close();
                    }
                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }

        }
    }

